Coupler apparatus for use with a tendon-receiving duct in a segmental precast concrete structure

ABSTRACT

A coupler apparatus for use with tendon-receiving duct in a segmental precast concrete structure including a coupler body having an interior passageway for receiving the duct therein. The coupler body has a generally U-shaped channel formed at one end thereof. The coupler element has a connector element formed on interior thereof adjacent one end of the coupler body so as to allow the coupler element to receive a variety of implements for the formation of the precast concrete segment.

RELATED U.S. APPLICATIONS

[0001] The present application is a continuation-in-part of U.S. patentapplication Ser. No. 10/139,798 filed on May 7, 2002, and entitled“Symmetrical Coupler Apparatus for Use with Precast ConcreteConstruction”, presently pending.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

REFERENCE TO MICROFICHE APPENDIX

[0003] Not applicable.

FIELD OF THE INVENTION

[0004] The present invention relates to the assembly and installation ofprecast concrete segments used in construction activities, such asbridge and highway construction. More particularly, the presentinvention relates to couplers for joining the ends of interior ducts ofsuch precast concrete segments in end-to-end liquid-tight relationship.

DESCRIPTION OF THE PRIOR ART

[0005] Precast segmental bridges are known and commonly used throughoutthe world as a means to forge roadways through mountainous terrain oracross rivers or other barriers. Such bridges are typically constructedin accordance with the following sequence: First, a series of uprightpiers are formed along the bridge span. Thereafter, cantilevered bridgesection are built out of each pier by successively mounting the precastsegments to previously completed bridge components and post-tensioningthe segments thereto. The cantilevered bridge sections are built outfrom each pier in a symmetrical fashion so that the piers are notsubjected to undue bending loads. When the cantilevered sections arecomplete, the ends thereof are post-tensioned together to form acontinuous bridge deck. Typically, two such bridge spans are constructedto accommodate the two directions of travel. These spans are generallyside-by-side, but need not be parallel (horizontally or vertically) norat the same elevation.

[0006] FIGS. 1-4 illustrate a form of such precast segmental bridgeconstruction in accordance with the teachings of U.S. Pat. No.5,231,936, issued on Aug. 3, 1993 to G. Sauvagiot. This form ofsegmental precast bridge construction is particularly disclosed as usedwith a rapid transit viaduct system.

[0007] Referring to FIG. 1, a rapid transit viaduct section two includesa central load bearing span or body member 4 supported by a pair ofupright pier members 6 and 8. Extending laterally from opposite lowerside portions of the central body 4 are a pair of lateral platformstructures 10 and 12. Each of the platform structures 10 and 12 has apair of rails 14 mounted thereon for carrying a rapid transit vehicle.In addition, each of the platform sections may be provided with anupright sidewall section 16 as required for safety, noise pollution andother considerations. One or more sets of rails 14 are carried by eachof the lateral platform structures depending on the requirements of thetransit systems.

[0008] The platform structures 10 and 12 each include respective upperplatform decks and respective lower support struts 22 and 24. The lowersupport struts 22 and 24 are mounted as close to the bottom of thecentral load bearing body 4 as practicable. Deck members 18 and 20 aremounted to the central body 4 at an intermediate portion thereof abovethe support struts 22 and 24. The support struts angle upwardly fromtheir point of attachment with the load bearing body 4 until theyintersect the deck members. As such, the deck members 18 and 20 andsupport struts 22 and 24 form a box section providing resistance totorsional loading caused by track curvature and differential trainloading. This box section may be considered a closed base. The loadbearing body 4 bisects the closed base and extends vertically upwardlytherefrom to provide span-wise bending resistance. Preferably, theentire duct section 2 is cast as a single reinforced concretecross-section.

[0009] The platform sections 10 and 12 each include lower pier mounts 26and 28. These are mounted respectively to the bottom of the supportstructures 22 and 24. The pier mounts 26 and 28 are, in turn, supported,respectively, on the piers 6 and 8 using a plurality of neoprene pads30, which provide a cushioned support for the structure.

[0010] As shown in FIG. 1, the viaduct section 2 forms part of a viaductsystem supporting rails 14 for carrying rapid transit vehicles 32 and34. The viaduct section 2 may be formed as a precast modular segment.The viaduct section 2 is then combined with other viaduct sections toform a precast segmental structure. To facilitate such construction, theload bearing body 4 may be formed with interlock member 36, while thelateral platform structures 10 and 12 may be each formed with interlockmembers 38.

[0011] Referring to FIG. 2, a viaduct system is formed from a pluralityof precast sections 2 formed as modular segments and combined as aprecast segmental structure extending between sequentially positionedpiers (not shown). The sections 2 are placed in longitudinally abuttingrelationship. To facilitate that construction, the sections are matchcast so that the abutting end portions thereof fit one another in anintimate interlocking relationship. Each successive section is thereforcast against a previously cast adjacent section to assure interfacecontinuity.

[0012] The connection between adjacent modular sections is furthersecured by way of the interlock members 36 and 38. On one end of eachsection 2, the interlock members 36 and 38 are formed as external keys.On the opposite end of each section 2, the interlock members are formedas an internal slot or notch, corresponding to the key members of theadjacent viaduct system. Match casting assures that corresponding keysand slots, as well as the remaining interface surfaces, properly fit oneanother.

[0013] As seen in FIG. 2, the sections 2 are bound together with one ormore post-tensioning cables or tendons 40, 42 and 44. The number ofcables used will depend on a number of factors such as cable thickness,span length and loading requirements. The tensioning cables are eachrouted along a predetermined path which varies in vertical or lateralposition along the span of the segmental structure.

[0014]FIG. 3 illustrates, diagrammatically, the manner in which thepost-tensioning cables 40, 42 and 44 extend through the concretestructure of the spans. As can be seen in FIG. 3, the post-tensioningcables are sometimes positioned within the concrete segment themselves,and at other times are positioned externally thereof.

[0015] It is important to note that multiple post-tension cables areoften used as extending through ducts within the concrete structure. InFIG. 4, it can be seen that the sections 2 are formed with appropriateguide ducts 50 at locations where the post-tensioning cables passedthrough the structure. The post-tensioning cable identified collectivelyby reference numeral 52 in FIG. 4, are routed through the guide ducts50. To facilitate this routing, a continuous flexible conduit 54 isinitially inserted through the guide ducts, and the post-tensioningcables 52 are thereafter placed in the conduit. The conduit 54 mayadvantageously be formed from polyethylene pipe but could also be formedfrom flexible metallic materials. The post-tensioning cables 52 aretensioned using conventional post-tensioning apparatus and the interiorof the conduit 54 is cement grouted along the entire length thereof forcorrosion protection.

[0016] One form of duct that is commercially available is shown in FIG.5. The corrugated polymeric duct 56 is of a type presently manufacturedby General Technologies, Inc. of Stafford, Tex., licensee of the presentinventor. As can be see in FIG. 5, duct 56 has a plurality ofcorrugations 58 extending radially outwardly from the generally tubularbody 60. The duct 56 has ends 62 and 64 through which post-tensioningcables can emerge. In FIG. 5, it can be seen that there are longitudinalchannels 66, 68 and 70 extending along the outer surface of the tubularbody 60. The longitudinal channels 66, 68 and 70 allow any grout that isintroduced into the interior of the duct 56 to flow easily and fullythrough the interior of the duct 56. The longitudinal channels 66, 68and 70 also add structural integrity to the length of the duct 56. It isimportant to realize that the duct 56 can be formed of a suitable lengthso as to extend fully through one of the segments 2 as used in a precastsegmental structure.

[0017] Unfortunately, when such ducts, such as duct 56, are used in suchprecast segmental construction, it is difficult to seal the ends 62 and64 of each duct to the corresponding duct of an adjacent section of thesegmental structure. Conventionally, the segments are joined together inend-to-end relationship through the application of an epoxy material tothe matching surfaces of the structure. Under such circumstances, it isvery common for the epoxy to flow or to become extruded into the openingat the ends 62 and 64 of the duct when the segments are connected inend-to-end relationship. In other circumstances, a grout is pumpedthrough the interior passageway of the duct 56 so as to offer a sealagainst the intrusion of air and water into the interior of the duct 56.The grout is pumped through the interior of the ducts. Unfortunately, ifthere is an incomplete connection between the duct 56 and the duct of anadjoining segment of the segmental structure, then the epoxy will leakout into the interface area between the segments and will not flow fullythrough the entire duct assembly. Once again, an incomplete grouting ofthe interior of the duct 56 may occur.

[0018] It is important to note that in such precast concrete segmentalconstruction, the concrete will slightly warp when matched with theadjoining section. Even though match casting is employed, the lack ofhomogeneity in the concrete mixtures used for the adjoining sections cancause a misalignment between matching sections. A great deal oftolerance must maintained when a coupler is developed so that anywarping or distortion in the surfaces of the matching segments can beaccommodated.

[0019] The ability to avoid air and liquid intrusion into the interiorof the duct 56 is very important in such multi-strand, precast concretesegmental structures. As can be seen in FIG. 1, since the structure isoften used on bridges or elevated structures, the post-tensioning cablescan be subject to a great deal of exposure from the elements. Forexample, if the bridge structure is associated with roads traveled bymotor vehicles, then there is often the application of salt onto thehighway. This salt, when dissolved in water, can leach through the areabetween the structure segments into the ducts and deteriorate thepost-tensioning cables over time. As the post-tensioning cables becomecorroded, over time, they can weaken so as to potentially cause thefailure of the segmental structure. Past experience with such structureshas shown that the primary area of leakage would be through those crackformed between those matched segments. As such, it is particularlyimportant to provide a coupler for use in association with the plasticducts which will effectively prevent any liquid intrusion from enteringthe area interior of the ducts and adjacent to the post-tensioningcables.

[0020] It is an object of the present invention to provide a couplerapparatus which allows for the coupling of multi-tendon ducts in precastsegmental concrete structures.

[0021] It is another object of the present invention to provide acoupler apparatus which automatically adjusts for any misalignments orwarpage in the matching concrete segments.

[0022] It is another object of the present invention to provide acoupler apparatus which assures a seal between the coupler and theconnected duct.

[0023] It is still a further object of the present invention to providea coupler apparatus which is easy to install, easy to use and easy tomanufacture.

[0024] It is still a further object of the present invention to providea coupler apparatus which effectively prevents the intrusion of an epoxyinto the interior of the duct during the sealing of one structuralsegment to another structural segment.

[0025] It is a further object of the present invention to provide asymmetrical duct coupler which facilitates the ability to manufactureand install the components thereof.

[0026] These and other objects of the present invention will becomeapparent from a reading of the attached specification and appendedclaims.

SUMMARY OF THE INVENTION

[0027] The present invention is a coupler apparatus for use withconcrete segments that comprises a first duct having an end and anexterior surface, a first coupler member extending over and around theexterior surface of the duct and having an end opening adjacent to anend of the first duct, a second duct having an end and an exteriorsurface, a second coupler member extending over and around the exteriorsurface of the second duct and having an end opening adjacent to the endof the second duct, a first gasket received within the end of the firstcoupler member and a second gasket received within the end of the secondcoupler member. The first coupler member and the second coupler memberare connected together such that the first gasket is in sealing contactwith the second gasket.

[0028] In the present invention, a first external seal is affixed ingenerally liquid-tight relationship to an opposite end of the firstcoupler member and affixed to an exterior surface of the first duct. Asecond external seal is affixed in generally liquid-tight relationshipto an opposite end of the second coupler member and affixed to anexterior surface of the second duct. The external seal is formed of aheat shrink material. The external seals are in compressive contact withthe respective exterior surfaces of the coupler members and with theexterior surfaces of the respective ducts.

[0029] In the present invention, an end of the first coupler member hasa generally U-shaped channel facing the second coupler member. Thesecond coupler member also has a generally U-shaped channel facing thefirst coupler member. The first gasket is fitted within the channel ofthe first coupler member. The second gasket is fitted into the channelof the second coupler member. Each of the first and second couplermembers has a flange element extending radially outwardly therefrom.This flange element is positioned inwardly away from the end of therespective coupler members. The first coupler member also a connectorelement extending around an interior of the coupler member adjacent tothe end of the coupler member. This connector element is in the form ofa protrusion extending inwardly from a wall around the interiorpassageway.

[0030] In the present invention, each of the gaskets is an elastomericring having a cross-sectional thickness greater than a depth of eitherof the respective channels of the first and second coupler members. Thefirst duct, the second duct, the first coupler member and the secondcoupler member are each formed of a polymeric material. The firstcoupler member has an identical configuration to that of the secondcoupler member.

[0031] The present invention is also a coupler apparatus for use with atendon-receiving duct in a segmental precast concrete structure. Thiscoupler apparatus includes a coupler body having an interior passagewaysuitable for receiving the duct therein. The coupler body has agenerally U-shaped channel formed at one end thereof. The couplerelement has a connector element formed on an interior thereof adjacentone end of the coupler body. The coupler body also has a flange elementextending radially outwardly therefrom and positioned inwardly away fromone end of the coupler body.

[0032] In the coupler apparatus, a form plug can be removably receivedwithin the interior passageway of the coupler body so as to extendoutwardly of this end of the coupler body. The form plug seals one endof the body over the interior passageway. In particular, the form plughas a groove extending therearound. This groove of the form plug engagesthe protrusion extending from the interior wall of the coupler body.

[0033] In the present invention, a blockout element is removably fittedwithin the U-shaped channel so as to close off an interior of thechannel. Additionally, a match cast plug is removably received withinone end of the coupler body. This match cast plug has a protrusionextending outwardly of one end of the coupler body. The match cast plughas a groove extending therearound. This groove engages the protrusionformed on the interior wall of the coupler body. The match cast plugalso has a shoulder formed centrally on an exterior surface thereof.This shoulder is an abutment with one end of the coupler body.

[0034] In the present invention, a gasket is received within theU-shaped channel of the coupler body. This gasket is an elastomeric ringhaving a cross-sectional thickness greater than a depth of the U-shapedchannel. An external seal is in compressive contact with an opposite endof the coupler body. This external seal has a portion extendingoutwardly beyond this opposite end of the coupler body. The externalseal is of a heat shrink material. The external seal is sealed onto anexternal surface of the coupler body. A concrete segment surrounds anexterior surface of the coupler body. One end of the coupler body opensat a surface of the concrete segment.

[0035] Additionally, and furthermore, the coupler apparatus of thepresent invention can include a cap that is removably affixed over thegasket. This cap has an insert portion received within the interiorpassageway of the coupler body. The insert portion has a groove formedtherearound. The protrusion formed on the interior wall of the couplerbody engages the groove on the cap so as to retain the cap in itsdesired position over the gasket during transport.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0036]FIG. 1 is a diagrammatic view showing a cross-section of a rapidtransit viaduct structure employing a prior art precast segmentalstructure.

[0037]FIG. 2 is a partially diagrammatic view showing a cross-sectionindicating the assemblage of the concrete segments of the structure ofFIG. 1 and showing, in particular, the alignment of the post-tensioningcables.

[0038]FIG. 3 is an end view of a precast concrete segment, and theassociated post-tension cables, of the prior art structure if FIG. 1.

[0039]FIG. 4 is a diagrammatic cross-sectional view showing the priorart techniques for the routing of a cable through the duct associatedwith the concrete segment.

[0040]FIG. 5 is a side elevational view of a prior art multi-cable ductas used in the present invention.

[0041]FIG. 6 is a cross-sectional view showing the coupler assembly asused in the precast concrete segmental structure of the presentinvention.

[0042]FIG. 7 is a cross-sectional view showing the assembly of thecoupler apparatus of the present invention.

[0043]FIG. 8 is an exploded cross-sectional view showing the assembly ofthe coupler apparatus of the present invention.

[0044]FIG. 9 is an exploded view of the initial arrangement ofcomponents of the coupler apparatus of the present invention during theformation of the concrete segment.

[0045]FIG. 10 is a cross-sectional view showing the coupler apparatus ofthe present invention as secured to a form board.

[0046]FIG. 11 is a cross-sectional of the coupler apparatus of thepresent invention as removed from the form board.

[0047]FIG. 12 is a cross-sectional showing the initial installation ofan adjoining coupler apparatus for the match casting of an additionalconcrete segment.

[0048]FIG. 13 is a cross-sectional view showing the coupler assembly ofthe present invention during the formation of the match cast segment.

[0049]FIG. 14 is a cross-sectional view of the present invention showingthe assembled segment as separated from the match casting.

[0050]FIG. 15 is an exploded cross-sectional view showing thearrangement of a protective cap for fitting over the gasketed end of thecoupler apparatus during transport.

DETAILED DESCRIPTION OF THE INVENTION

[0051] Referring to FIG. 6, there is shown at 100 the precast concretesegmental structure in accordance with the teachings of the presentinvention. The structure 100 includes a first concrete segment 102 and asecond concrete segment 104. The first concrete segment 102 has asurface 106 which is joined in surface-to-surface contact with thesurface 108 of the concrete segment 104. The segments 102 and 104 areformed by match casting, as described hereinbefore and as will bedescribed hereinafter.

[0052] Importantly, a first duct 110 is embedded in the first concretestructure 102. Duct 110 has a construction similar to that shown in FIG.5, or similar to other multi-cable ducts. The first duct 110 has an end112 generally adjacent to the surface 106 of the concrete segment 102.Similarly, a second duct 14 is embedded in the second concrete segment104. The second duct 114 has a configuration similar to that of duct110. Duct 114 has an end 116 generally adjacent to the surface 108 ofconcrete segment 104. Each of the ducts 110 and 114 are embedded in therespective concrete segments 102 and 104 so as to be generallylongitudinally aligned. The duct 110 has an interior passageway whichwill be axially aligned with the interior passageway of duct 114.

[0053] A plurality of tendons will extend longitudinally through theinterior passageways of the ducts 110 and 114. The tendons will beproperly post-tensioned in a conventional manner and as describedhereinbefore. A grouting material can be introduced through the interiorpassageways 110 and 114 to further cement and seal the interior of theducts 110 and 114 around the tendons. The grouting material, incombination with the polymeric material of the ducts 110 and 114, servesto avoid the adverse effects of liquid intrusion into the tendons. Thepresent invention utilizes a unique coupler apparatus 122 which furtherassures the avoidance of liquid intrusion through the space between thesurface 106 of concrete segment 102 and the surface 108 of concretesegment 104. A first coupler member 124 extends over and around theexterior surface of the first duct 110. The first coupler member 124 hasan end 126 opening at the surface 106 of concrete segment 102.Similarly, the end 126 of the coupler member 124 is generally forwardof, but adjacent to, the end 112 of first duct 110. A second couplermember 128 extends over and around the exterior surface of the secondduct 114. The second coupler member 128 has an end 130 opening at thesurface 108 of concrete segment 104. End 130 is slightly forward of theend 116 of the duct 114. A first gasket 131 is received in the end 126of the coupler member 124. A second gasket 133 is received within theend 130 of the coupler 128. The gaskets 131 and 133 are in compressivecontact with each other so as to prevent liquid from passing between theends 126 and 130 of the respective coupler members 124 and 128 into theinterior of the ducts 110 and 114. The coupler members 124 and 128 havean identical configuration to each other. This serves to minimize themanufacturing requirements since only a single mold is required for eachof the coupler members. Also, installation is simplified since unskilledworkers can install the first and second coupler members without regardto the configuration of a particular coupler member.

[0054] An external seal 134 is affixed in generally liquid-tightrelationship to an opposite end 136 of the first coupler member 124 andis also affixed to an exterior surface of the first duct 110. Inparticular, the external seal 134 is formed of an elastomeric sleeve orof an annular heat shrink material. The external seal 134 will be incompressive liquid-tight contact with the exterior surface of the firstcoupler member 124 and with the exterior surface of the duct 110. Priorto embedding the coupler member 124 into the concrete associated withthe concrete segment 102, the coupler member 124 can be affixed inliquid-tight relationship by applying heat to the exterior surface ofthe external seal 134. The heat-shrink material of the external seal 134will tightly engage the surfaces of the coupler member 124 and also theexterior surfaces of the duct 110. As a result, the exterior surface 134will prevent liquid intrusion through the opposite end 136 of thecoupler member 124.

[0055] Similarly, an external seal 138 in affixed in generallyliquid-tight relationship to an opposite end 139 of the second couplermember 128 and also is affixed to an exterior surface of the second duct114. In particular, this external seal 138 is also formed of anelastomeric sleeve or an annular heat shrink material, similar to thatof external seal 134. The external seal 138 will be in compressiveliquid-tight contact with the exterior surface of the second couplermember 128 and with the exterior surface of the duct 114. The externalseal 138 is applied to the second coupler member 128 and to the secondduct 114 in the same manner that the external seal 138 was applied overthe first coupler member 124 and onto the first duct 110. As a result,the external seal 134 will prevent liquid intrusion through the oppositeend 139 of the coupler member 128.

[0056] In FIG. 7, it can be seen that the end 126 of the first couplermember 124 has a generally U-shaped channel 141 facing the secondcoupler member 128. In particular, it is the opening of this U-shapedchannel which faces the second coupler member 128. Similarly, the end130 is also a U-shaped channel 143 which faces the U-shaped channel 141.It can be seen that the first gasket 131 is fitted within the opening ofthe U-shaped channel 141. Similarly, the second gasket 133 is fittedwithin the opening of the U-shaped channel 143. A flange element 145extends radially outwardly from a side of the first U-shaped channel141. Similarly, a flange element 147 extends radially outwardly from theU-shaped channel 143. The arrangement of these flange members 145 and147 will further assure the accurate placement and retention of the ends126 and 130 of the coupler members 124 and 128 within the respectiveconcrete blocks 102 and 104.

[0057] The gaskets 131 and 133 are elastomeric rings having across-sectional thicknesses greater than a depth of either of therespective channels 131 and 133 at the ends 126 and 130 of the couplermembers 124 and 128. As a result, the elastomeric rings of the gaskets131 and 133 will effectively “fill” the entirety of the open areas ofthe channels 141 and 143. The configuration of the channels 141 and 143causes the elastomeric material of the gaskets 131 and 133 toeffectively cause a tight sealing relationship thereagainst.

[0058] In the present invention, a small protrusion 151 extends inwardlyfrom an inner wall 153 of the first coupler member 124. The protrusion151 will extend around the inner wall and around the interior passageway155. Similarly, another small protrusion 157 extends inwardly from theinner wall 159 of the second coupler member 128. These protrusions 151and 157 facilitate the ability to connect various items for theformation of the segmental blocks, as will be described hereinafter.Each of the small protrusions 151 and 157 can be considered theconnecting elements associated with each of the coupler members 124 and128.

[0059] Importantly, the present invention is of relatively low cost. Thefirst duct 110, the second duct 114, the first coupler member 124 andthe second coupler member 128 are formed of a polymeric material. Eachof these components can be formed in an injection molding process.Similarly, the gaskets 131 and 133 can be formed of an elastomericmaterial or other resilient material. The material used for the gaskets131 and 133 should be suitably hydrophobic so as to resist any liquidintrusion.

[0060]FIG. 8 is an illustration of the apparatus 100 of the presentinvention prior to the installation of the tendons and the installationof the grout. In particular, FIG. 8 shows the initial assembly of thecomponents of the present invention. As can be seen, the first couplermember 124 is axially aligned so that the interior passageway 155thereof is aligned with the interior passageway 161 of the secondcoupler member 128. Alternatively, it can be considered that theinterior passageway of the respective ducts 110 and 114 are aligned witheach other. The surface 106 of concrete segment 102 faces the surface108 of concrete segment 104. These segments 102 and 104 are broughttogether until the gaskets 131 and 133 establish a sealing contact witheach other. Once joined together, the seals 131 and 133 will effect aseal so as to prevent liquid intrusion into the interior passageways 155and 161. Tendons and grout can then be installed into the interiorpassageways 155 and 161 of the respective ducts 110 and 114.

[0061] The present invention closely relates to the initial formation ofthe concrete segment. The initial steps in the formation of the concretesegment are illustrated in FIG. 9. As can be seen in FIG. 9, the couplermember 124 has U-shaped channel 141 extending at end 126 thereof. Theopposite end 136 has been sealed with external seal 134 to the exteriorsurface of duct 110. The duct 110 is positioned on the interior of thefirst coupler member 124 such that the end 112 faces outwardly of theend 126 of coupler member 124.

[0062] Initially, a blockout element 160 is positioned into the interior163 of channel 141. The blockout element 160 is removably fitted withinthe interior 163 so as to effectively close off the interior 163 ofchannel 141. The blockout element 160 will extend around the peripheryof the end 126 by a small shoulder 162 formed around the periphery ofthe blockout element 160. The blockout element 160 is an annular elementwhich has an interior opening 164 generally corresponding in size to theopening at the end 166 of the coupler member 124.

[0063] A form board 168 can be placed against the outer surface 170 ofthe blockout element 160. The form board 168 will have opening 171formed therein. Opening 171 will correspond axially to the opening 164of blockout element 160.

[0064] In order to secure the end 166 of the coupler member 124 againstthe form board 168 such that the blockout element 160 is interposedtherebetween, a form plug 174 is inserted through the opening 171, theopening 164 and into the interior 155 of the coupler member 124. Theform plug 174 has a cap portion 176 formed at one end thereof. The capportion will have an inner surface 178 residing in surface-to-surfacecontact with the exterior surface 180 of form board 168. An insertportion 182 of the form plug 174 will pass through the opening 171 andthrough the opening 164 so as to reside within the interior 155 of thecoupler member 124. A small groove 184 formed around the periphery ofthe insert portion 182 will be releasably engaged with the protrusion151 formed on the inner wall of the coupler member 124. As such, theform plug 174 will retain the blockout element 160 and the couplermember 124 in their desired position relative to the form board 168.

[0065]FIG. 10 shows the placement of the form plug 174 within the formboard 168 such that the insert portion 182 engages the interior of thecoupler member 124. As a result, the duct 110 is properly aligned withrespect to the form board 168 and in a suitable so that the concrete canbe poured thereover. It can be seen that the blockout element 160 issuitably positioned so as to cover the interior 163 of channel 141 andto be placed in surface-to-surface contact with an inner wall of theform board 168. FIG. 10 also shows that the groove 184 engages theprotrusion 151 of the coupler member 124.

[0066] In FIG. 11, it can be seen that the concrete 102 has been pouredaround the coupler member 124 and the duct 110. The concrete 102 issuitably solidified against the inner wall 190 of the form board 168 soas to present flat surface 106 at the end of the concrete segment. Theblockout element 160 will have a surface coplanar with the surface 106.Similarly, the end 126 of the coupler member 124 will be flush withsurface 106. The form board 168, along with the form plug 174, can besuitably removed by separating the insert portion 182 such that thegroove 184 separates from the protrusion 151 in an easy and convenientmanner. After the form board 168 is removed, the segment is suitable foruse in association with match casting.

[0067]FIG. 12 shows the next step in the process, which involves theinsertion of a match cast plug 200 into the interior 155 of the couplingmember 124. The blockout element 160 will remain in its position withinthe interior 163 of channel 141. The match cast plug 200 is an annularbody of polymeric material and of generally symmetrical shape on eachside of a center line thereof. Importantly, the match cast plug 200 hasan insert portion 202 which can be placed into the interior of thecoupling member 124. A small groove 204 is formed on the exteriorsurface of the match cast plug 200. Groove 204 can suitably detachablyengage the protrusion 151 so as to retain the match cast plug 200 in adesired position. A shoulder 206 is formed on the outer periphery of thematch cast plug 200. The end 166 of the coupler member 124 will be inabutment with the shoulder 206. As a result, the proper positioning ofthe match cast plug 200 is assured.

[0068] The second coupler member 128 is configured in a similar manneras that of the first coupler member 124. The second coupler member 128has an interior passageway 161 therein. The interior passageway 161 willface the match cast plug 200 and be directed so as to be placedthereover. The second coupler member 128 also has a protrusion 157 whichis suitable for placement within the groove 208 formed on the exteriorsurface of the match cast plug 200.

[0069]FIG. 13 shows the placement of the second coupling member 128against the surface 106 of the block 102 such that the end of the secondcoupler 128 is placed over another insertion portion of the match castplug 200 and such that the groove 208 receives the protrusion 157 of thesecond coupler member 128. As a result, the proper and exact alignmentof the second coupler member 128 with the first coupler member 124 isassured. Concrete can then be poured over the exterior surfaces of thesecond coupler member 128, along with the duct 114, so as to form thematch cast segment thereover.

[0070]FIG. 14 shows that the concrete segment 104 has been formed withflat surface 108. Flat surface 108 will match the flat surface 106 ofthe concrete segment 102. The segment 104 will then have a properconfiguration whereby, during installation, the surfaces 106 and 108will properly match so that the coupler members 124 and 128 willproperly align during actual installation and post tensioning. After thesegment 102 is separated from the segment 104, the blockout elements 160and 220 can be removed from the respective channels 141 and 143.Similarly, the match cast plug 200 can be simply pulled from the openingat the end of the second coupler member 124. As a result, the separatesegments 102 and 104 of coupler apparatus 100 will be ready forinstallation in the manner as shown in FIG. 6.

[0071]FIG. 15 shows that the gasket 131 has been installed withinchannel 141. It can be seen that the gasket 131 has a cross-sectionalthickness which is greater than the depth of the interior 163 of thechannel 141. As such, there is a surface 230 which extends outwardlybeyond the end 126 of the coupling member 124.

[0072] So as to properly protect the gasket 131 and the end 126 ofcoupling member 121 during lifting and installation of the concrete 102,a cap 240 can be placed thereover. Cap 240 is formed of a rigidpolymeric material and has an insert portion 242. Insert portion 242includes a small groove 244 extending therearound. Groove 244 issuitably compatible with the notch so as to allow for the detachablereceipt of the insert portion 242 within the interior 155 of thecoupling member 144. The cap 240 also has a covering portion 246 whichextends outwardly therefrom so as to cover the outer surface of thegasket 131. As a result of the installation of the cap 240 over the end126 of the coupling member 124, the gasket 131 will be effectivelyprotected during the lifting, moving and installation of the concretesegment 102 in the construction project. In the present invention, itcan be seen that the small connection element 151 can be in the form ofeither a protrusion extending outwardly from the inner wall from thecoupler member 124 or could be, in reverse, a small groove formed on theinner wall of the coupler member 124. In this alternative form, aprotrusion would be formed on the insert portions on the variouscomponents used for the formation of the segmental coupling of thepresent invention. Additionally, the small connection element 151facilitates the ability to properly position, install and retain thevarious components during the assembly process associated with thesegmental construction. The connector element 151 works effectivelywithout creating a barrier or a difficulty during the installation ofthe tendons within the interior of the duct. The protrusion can takevarious forms such as the angled orientation of the protrusion 151 asillustrated in FIG. 15.

[0073] In the present invention, the unique configuration of the gaskets131 and 133, along with the channels 141 and 143, will avoid anyintrusion of epoxy into the interior passageways 155 and 161. Thegaskets 131 and 133 will block the extruded epoxy from flowing in anundesired manner into the interior passageways 155 and 161. In a similarmanner, the gaskets 131 and 133 will also prevent any liquid intrusionfrom passing into these interior passageways. The compressiverelationship between the gaskets 131 and 133 will establish a strongsealing bond between the coupler members 124 and 128 which will beresistive to the elements over an extended period of time. Subsequent toinstallation, the grout can be effectively pumped through the interiorpassageways 155 and 161 without any grout accidentally flowing outwardlyof the ducts 110 and 114 in the area of the space between the segments102 and 104. Secondary liquid intrusion is effectively prevented throughthe tight sealing relationship of the external seals 134 and 138.

[0074] The foregoing disclosure and description of the invention isillustrative and explanatory thereof. Various changes in the details ofthe illustrated construction may be made within the scope of theappended claims without departing from the true spirit of the invention.The present invention should only be limited by the following claims andtheir legal equivalents.

I claim:
 1. A coupler apparatus for use with concrete segments comprising: a first duct having an end and an exterior surface; a first coupler member extending over and around said exterior surface of said duct, said first coupler member having an end opening adjacent said end of said first duct; a second duct having an end and an exterior surface; a second coupler member extending over and around said exterior surface of said second duct, said second coupler member having an end opening adjacent said end of said second duct; a first gasket received in said end of said first coupler member; and a second gasket received in said end of said second coupler member, said first coupler member and said second coupler member being connected together such that said first gasket is in sealing contact with said second gasket.
 2. The coupler apparatus of claim 1, further comprising: a first external seal affixed in generally liquid-tight relationship to an opposite end of said first coupler member and affixed to an exterior surface of said first duct; and a second external seal affixed in generally liquid-tight relationship to an opposite end of said second coupler member and affixed to an exterior surface of said second duct.
 3. The coupler apparatus of claim 2, each of said first and second external seals being formed of a heat shrink material, said first external seal being in compressive contact with an exterior surface of said first coupler member and with said exterior surface of said first duct, said second external seal being in compressive contact with an exterior surface of said second coupler member and with said exterior surface of said second duct.
 4. The coupler apparatus of claim 1, said end of said first coupler member having a generally U-shaped channel facing said second coupler member, said second coupler member having a generally U-shaped channel facing said first coupler member, said first gasket fitted in the U-shaped channel of at least one of said first coupler member, said second gasket fitted in the U-shaped channel of at least one of said second coupler member.
 5. The coupler apparatus of claim 4, said first coupler member having a flange element extending radially outwardly therefrom, said flange element positioned inwardly away from said end of said first coupler member.
 6. The coupler apparatus of claim 1, said first coupler member having a connector element extending around an interior of said first coupler member adjacent said end of said first coupler member.
 7. The coupler apparatus of claim 4, each of said first and second gaskets being an elastomeric ring having a cross-sectional thickness greater than a depth of either of the respective U-shaped channels of said first and second coupler members.
 8. The coupler apparatus of claim 1, said first duct and said second duct and said first coupler member and said second coupler member each being formed of a polymeric material.
 9. The coupler apparatus of claim 1, said first coupler member having an identical configuration as said second coupler member.
 10. A coupler apparatus for use on tendon-receiving ducts of a segmental precast concrete structure comprising: a coupler body having an interior passageway suitable for receiving the duct therein, said coupler body having a generally U-shaped channel formed at one end thereof, said coupler element having a connector element formed on an interior thereof adjacent said one end of said coupler body.
 11. The coupler apparatus of claim 10, said coupler body having a flange element extending radially outwardly therefrom and positioned inwardly away from said one end of said coupler body.
 12. The coupler apparatus of claim 10, further comprising: a form plug removably received within said interior passageway of said coupler body so as to extend outwardly of said one end of said coupler body, said form plug sealing said one end of said body over said interior passageway.
 13. The coupler apparatus of claim 12, said connector element being a protrusion extending inwardly from a wall around said interior passageway, said form plug having a groove extending therearound, said groove of said form plug engaging said protrusion of said connector element.
 14. The coupler apparatus of claim 10, further comprising: a blockout element removably fitted within said U-shaped channel so as to close off an interior of said channel.
 15. The coupler apparatus of claim 10, further comprising: a match cast plug removably received within said one end of said coupler body, said match cast plug having a portion extending outwardly of said one end of said coupler body.
 16. The coupler apparatus of claim 15, said connector element being a protrusion extending inwardly of a wall around said interior passageway, said match cast plug having a groove extending therearound, said groove of said match cast plug engaging said protrusion of said connector element.
 17. The coupler apparatus of claim 15, said match cast plug having a shoulder formed centrally on an exterior surface thereof, said shoulder being in abutment with said one end of said coupler body.
 18. The coupler apparatus of claim 10, further comprising: a gasket received within said U-shaped channel of said coupler body.
 19. The apparatus of claim 18, said gasket being an elastomeric ring having a cross-sectional thickness greater than a depth of said U-shaped channel.
 20. The apparatus of claim 18, said connector element being a protrusion extending inwardly form a wall around said interior passageway, the coupler apparatus further comprising: a cap removably affixed over said gasket, said cap having an insert portion received within said interior passageway at said one end, said insert portion having a groove formed therearound, said protrusion engaging said groove.
 21. The apparatus of claim 10, further comprising: an external seal in compressive contact with an opposite end of said coupler body, said external seal having a portion extending outwardly beyond said opposite end.
 22. The apparatus of claim 21, said external seal being of a heat shrink material, said external seal being sealed onto an exterior surface of said coupler body.
 23. The apparatus of claim 10, further comprising: a concrete segment surrounding an exterior surface of said coupler body, said one end of said coupler body opening at a surface of said concrete segment. 